High-speed print drum with traveling print hammer



Jan. 23, 1968 R. A. RAG-EN 3,364,852

HIGH-SPEED I RINT DRUM WITH TRAVELING PRINT HAMMER Filed Nov. 12, 1965 (OQNOIC' SELECTOR AND T i ACTUATOR MEANS 1 I I I I I I I I ru o Th -l cm III II m Ijijwmfl E III III II II D E II III III 0 00 \1 A LTEJEJLT I t g,lj.m [JIIIUIII [JED-I1 50 .EJEI UEI 7 EDGE! I j 4 o: m C

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DQOCONOUQB DQOQNCDU' ATTORNEY United States Patent 3,364,852 HIGH-SPEED PRINT DRUM WITH TRAVELING PRINT HAMMER Robert A. Rageu, Hayward, Califi, assignor to Friden, Inc, a corporation of Delaware Filed Nov. 12, 1965, Ser. No. 507,289 3 Claims. (Cl. 101-93) ABSTRACT OF THE DISCLOSURE This invention relates to high-speed automatic printers and, in particular, to a printing device that utilizes a rotary drum for presenting characters for printing.

Presently known high-speed printers generally incor- 3,354,852 Patented Jan. 23, 1968 Similar numerals refer to similar elements throughout the drawing.

With reference to FIGS. 1 and 2, a high-speed printer made in accordance with this invention includes a rotary drum 10, made of hardened steel, for example, mounted to a shaft 12 which is rotatably driven by a constant speed motor (not shown). On the surface of the drum 10, a multiplicity of raised characters 14, which may be alphabetical or numerical symbols, such as the numerals 0 through 9, are disposed in alternate annular columns 16, with blank annular columns 18 interposed between the character columns. The symbols in each character 1 column 16 are positioned to occupy less than 180 or porate a support for carrying characters or symbols to be imprinted, a hammer means for striking selected characters, a paper or record medium disposed adjacent to and between the character carrier and hammer for registering imprints, and drive means for imparting relative motion between the several elements. Each known apparatus encounters diiferent problems, such as an overabundance of mechanical and electronic parts with attendant complexity and wear and tear, resulting in expensive maintenance, repair and replacement, and loss of operating time.

An object of this invention is to provide a high-speed automatic printer that is simple in structure, relatively inexpensive, and easy to control.

' Another object of this invention is to provide a highspeed automatic printer that affords less type wear, and a minimum of operating noise.

According to this invention, a high-speed automatic printer comprises a rotary drum that supports a plurality of columns of characters on its periphery or surface, and a print hammer means that traverse the rotating drum for striking characters selected from the column sequentially. The movable print hammer spans two adjacent column positions, and during operation, the hammer is moved across the surface of the drum parallel to the drum axis at a substantially constant speed. Blank spaces in the form of blank columns or other patterns are interposed between the character columns or characters to allow the hammer to reset for potentially striking any character of each group, for each axial sweep across the rotating drum surface. In this manner, one character from each columnar group may be selected seriatirn to achieve printing of data or information which is supplied from a transmitter or storage means, for example.

This invention will be described'in greater detail with reference to the drawing, in which:

FIG. 1 is a plan view, partly in block, of a high-speed automatic printer, in accordance with this invention;

FIG. 2 is a side elevational view of part of the inventive apparatus of FIG. 1;

FIG. 3 is a representation of an arrangement of charac ters and symbols, including decimals, that may be used with the inventive apparatus; and

FIG. 4 is a representation of an alternative array of characters and symbols, partly broken away, useful with the present invention.

one-half of the drum periphery, the rest of the column being blank.

A print hammer mechanism 20 is located in juxtaposition to the drum 10 with a paper 22 or other recording medium secured therebetween. The print hammer 20 has a striker head with a width less than the combined width of two columns, but greater than the width of one column. An ink ribbon 24 is also disposed between the print hammer 20 and paper 22 to afford imprinting upon the striking of the hammer 20 against a raised character 14. Both the paper 22 and ink ribbon 24 may be separately transported relative to the drum and hammer by conventional supply and takeup means. With some presently known types of paper, the ink ribbon is not required for the printing process.

The print hammer 25 is supported by a carriage 26 that is driven longitudinally at substantially constant speed by means of an endless belt 28 carrying a pin 30, the pin being shown at start line" position in solid lines in FIG. 1 and at end-of-line position indicated by phantom line 30p. The belt 28 is rotated at substantially constant speed by a pair of similar pulley wheels 32 and 32a which' are shaft-driven by a constant speed motor (not shown). Thus, the carriage 26 may be moved along a path parallel to the axis of the drum 10 by means of fixed longitudinal guides or shafts (not shown).

In operation, the pin 30 engages the carriage 26 at the start position, indicated by solid lines in FIG. 1, and propels the carriage in a direction parallel to the axis of .the drum 12 to the end position, indi-catedby phantom tion 26p, ter column to be printed. Initially, at start position, the

, relative to the first pulley lines 26p. The start line position is determined so that the print hammerhead is in substantial alignment with the first two columns, i.e., the first character column and the first blank space column; while for the end-of-line posithe hammerhead is aligned with'the last characcarriage 26 is at rest, and is accelerated from zero velocity to the velocity of the endless belt 28. Such acceleration takes place during a 90 arcuate traverse of the pin 30 wheel 32, and is characterized by a smooth, uniform transition between line print cycles. Similarly, at the end-of-line, uniform deceleration of the carriage 26 is afforded by the arcuate travel of the pin 30 around the pulley wheel 32a.

When the carriage 26 is moved across the drum for printing, a resilient means or spring 34 is extended and tensed. The spring 34- is coupled at one end to a fixed support 36, which may be the frame of the apparatus, and at the other end is looped through an aperture 38 formed in the carriage 26. Upon reversal of direction of the pin 30 from end-of-line to start position, the

in a simple manner. It is understood .that various alternatives for driving the carriage 26 may be utilized, such as a cam, or rack and pinion, or worm gears, and the like.

During a sweep across the drum from start position to end-of-line position, the hammer 20 is actuated for striking a selected character 14 from each character column of the rotating drum 16 by a selector and actuator means 40 in a well known manner. The selector and actuator mean 40 may include information storage means, such as a shift register controlled by a magnetic tape, which stores predetermined permutations or combinations of binary data representing characters to be read out for printing and display. Suitable timing references, counters, and delay means may be utilized to energize a spring-biased solenoid 42 which allows the hammer 20 to strike a selected character precisely when the drum character is presented to print position. For this purpose, a coded timing wheel and sensing circuits may be utilized in conjunction with the shift register to achieve precise actuation of the striking hammer means relative to the rotation of the character drum.

In the embodiment set forth in FIG. 1, two characters may be printed for every complete revolution or 360 turn of the drum 10. Thus, when the start print mode begins, one character from the group in the first character column is selected for printing while the drum rotates continuously for less than 180. After firing of the print hammer 20, the hammer is reset while the carriage 26 transports the hammer in the axial direction of the rotating drum 10. Reset occurs as the hammerhead crosses the blank column 18 and approaches the character column 16 following the blank column. The hammer is moved into alignment with the second and third columns, which are respectively the first blank column 18 and second character column 16, and is again ready for striking a selected character from the group in the second character column. This second group of characters 14 is displaced 180 relative to the first group to accommodate the hammer 20 upon arrival. In the same way, all alternate character groups are displaced in opposite hemispheres of the drum periphery. It is noted that other arrangements of characters are possible within the scope of this invention, such that the displacement of adjacent columnar groups is 90, 120, and so forth.

FIG. 3 depicts another arrangement of characters on a drum that lends itself to the printing device of this invention. In this arrangement, the characters of each character column 44 are substantially in alignment. However, each column 46 interposed between the character columns 44 includes a decimal 48 positioned between blank spaces of the character columns. These blank spaces are preferably disposed substantially in the middle of the column character group, between the numerals 4 and 5, as illustrated. In such layout, the cylinder or drum rotates one full turn for each character column 44 and one 360 turn for each decimal column 46. In addition, other symbols 50 may be employed in separate columns 52, as illustrated.

Still another arrangement of characters on a drum surface is shown in FIG. 4, wherein the character columns 54 include a number of blank spaces, preferably the same in number as the print characters. Alternate character columns 54 are spaced by blank columns 56, each of which includes a decimal 58 located approximately midway of the spaces in the blank group of the character column. Different symbols 60 may be employed in one or more separate columns 62. All data characters are preferably in axial alignment or rows, and the blank spaces and decimals are similarly aligned in rows. This format may use one drum revolution per column, since the blank space groups will allow recocking of the hammer and recovery of the driving circuit.

It is evident that a multiplicity of schemes may be employed for arranging the characters on the periphery of a rotary drum, in accordance with this invention. For example, in a successful embodiment of the apparatus of FIG. 1, a drum of 1.269 inches diameter with columns of .100 inch width was employed, together with a hammer having a head width of approximately .140 inch. The apparatus was capable of printing thirty characters per second, with drum rotational speed of 900 r.p.m., and hammer longitudinal velocity of three inches per second. Such apparatus lends itself to faster printing speeds by merely increasing the speed of drum rotation, and accordingly hammer travel speed. In an embodiment of the arrangement illustrated in FIG. 3, a drum having a diameter of 0.7 inch and a column width of .150 inch was used. The hammerhead width was .140 inch, and the longitudinal velocity of the hammer was three inches per second. Rotational drum velocity was 3600 r.p.m., which enabled a print speed of thirty characters per second.

The apparatus described herein which includes, inter alia, a rotary character drum and print hammer that traverses the drum axially, is relatively inexpensive, uses a minimum of parts and is easy to maintain. Since the carriage supports only a hammer and its associated actuating parts, the mass being moved is relatively small, which affords less noise and less wear than previously known systems. Also, when compared to a device employing only a single column character wheel, it is seen that the present apparatus benefits from a reduction in type Wear. Furthermore, the circuitry including delays and timing networks, and the mechanical controls are the same for each columnar position, so that the characters in each printed line are accurately positioned linearly. In addition, the use of a single hammer with the same selection and delay circuitry and mechanical controls in lieu of a multiplicity of hammers, each with separate circuitry and parts, greatly reduces the complexity and cost of the presently disclosed printer system.

It should be understood that the invention is not limited to the particular embodiment described above. For example, the ink ribbon may be relocated or eliminated as stated heretofore. Also, it is possible to move the drum instead of the hammer, or move both, to accomplish relative motion between the rotary drum and hammer. In addition, the hammer need not be restricted to a continuous constant motion, but may be advanced stepwise to each print position, by use of a cam or gear means, if so desired.

What is claimed is:

1. A high-speed printer apparatus for imprinting characters on a medium comprising;

a cylindrical member having a plurality of annular columns on the periphery thereof,

alternate ones of said columns containing print characters with the other columns being blank,

means for rotating said cylindrical member about its axis,

a print hammer located in print relation with said cylindrical member and having a width that spansmore than one said column and less than two said columns,

means for continuously moving said print hammer in a direction parallel to the axis of said cylindrical member at a substantially constant velocity, and

means for causing said print hammer to strike said cylindrical member in response to a selected character being disposed in printing position with respect to said hammer while said print hammer is continuously moving at said constant velocity.

2. The apparatus of claim 1 wherein the print characters of each said character column are grouped with each group being disposed over a portion of its associated column position, adjacent character groups being angularly displaced relative to each other on the periphery of the cylindrical member, and predetermined nonadjacent character groups being in substantial axial alignment.

3. The apparatus of claim 1 wherein said character columns also include a blank character space and said blank columns include a print decimal character adjacent said blank space on said character columns.

References Cited UNITED STATES PATENTS Thiemann 10193 Potter 10193 Bernard 19755 Wilkins et a1. 10193 Christoff et a1 10193 Cerf 10193 Cogar 10193 WILLIAM B. PENN, Primary Examiner. 

